1. Field of the Invention
This invention relates to a unitary, one-piece, integrated, non-fragmenting overpressure vent panel assembly that may be installed in covering relationship to the pressure relief area of a combined zone to be protected from the buildup of uncontrolled overpressures, and to then be removed as a unit for replacement with a similar vent panel assembly after actuation thereof. The vent panel assembly is especially useful for instantaneously venting dangerously high internal pressures which result from an explosion in a manner to preclude catastrophic buildup of pressures within a confined area that is normally exposed to relatively low operating pressures. The vent panel assembly has utility for use in protecting equipment such as bag house dust collectors, cyclones, conveyors, bucket elevators, dryers, vacuum receivers, electrostatic precipitators, silos, storage bins, large pipes, and ducting.
2. Description of the Prior Art
Burst membranes or panels have been used for many years to provide protection against explosions producing unpredictable dangerously high internal pressures which not only would be destructive to the zone requiring protection, but also to surrounding equipment, processes and personnel. The burst panels are fabricated to rupture at a predetermined overpressure in order to vent the protected zone and prevent the buildup of pressures therein which in the case of an explosion could completely destroy the structure defining the protected zone.
Deployment of explosion vents has significantly increased in recent years because of the promulgation of ever more strict government regulations regarding the level of permissible particulates emissions that may be discharged into the atmosphere. The mandated adoption of dust collectors has correspondingly increased the risk of explosion inherent in the provision of such dust collecting equipment. The rise in the number of explosions attributable to particulates explosion has made it incumbent upon industry to provide effective means for adequately controlling the explosion problem. The need for explosion protection with improved dust collection equipment is exacerbated by the fact that the dust collectors tend to be less rigidly constructed and not as able to withstand internal explosions than was once the case. As a result, vent panels for venting the interior of dust collection apparatus must reliably rupture at a relatively low pressure in order to adequately vent the confined area to be protected before excessive pressure has built up within that area.
Examples of explosion vent devices that have been previously proposed include the vent panels and burst membranes illustrated and described in the assignee hereof U.S. Pat. Nos. 4,067,154, 4,662,126, 4,777,974, 4,821,909 and 6,070,365. Although these vent units have been found to be satisfactory for protection of a variety of dust collection applications where there is exposure to an unpredictable catastrophic explosive event, the prior vent panel devices have involved a multiplicity of parts which must be assembled in place over the vent opening of the confined zone to be protected, and to then be disassembled piece by piece upon venting of the burst panel of the explosion vent for replacement of the burst panel.
Typically, the operator of the dust collecting equipment has been responsible for providing suitable frame structure for receiving a burst panel with the supplier of the panel furnishing a burst membrane which complies with the dimensional specifications of the user's mounted in place frame structure. In the case of an initial installation, it is not uncommon for the burst panel supplier to provide the user with dimensional specifications for fabrication of frame structure required to mount a burst panel of standard configuration and dimensions established by the supplier. The burst panel is then mounted in place on the structure to be protected using hardware and fasteners supplied by the user.
Upon actuation of a burst panel by an overpressure condition in the structure to be protected, the actuated burst panel had to be removed from the structure defining a confined zone part by part, usually involving a number of steps and disconnection of a series of fasteners such as bolts and the like. Replacement of the panel required the same number of operations and steps to refit another burst panel over the pressure relief opening in the dust collecting structure.